// SPDX-License-Identifier: GPL-2.0-or-later /* Local endpoint object management * * Copyright (C) 2016 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/module.h> #include <linux/net.h> #include <linux/skbuff.h> #include <linux/slab.h> #include <linux/udp.h> #include <linux/ip.h> #include <linux/hashtable.h> #include <net/sock.h> #include <net/udp.h> #include <net/udp_tunnel.h> #include <net/af_rxrpc.h> #include "ar-internal.h" static void rxrpc_local_processor(struct work_struct *); static void rxrpc_local_rcu(struct rcu_head *); /* * Compare a local to an address. Return -ve, 0 or +ve to indicate less than, * same or greater than. * * We explicitly don't compare the RxRPC service ID as we want to reject * conflicting uses by differing services. Further, we don't want to share * addresses with different options (IPv6), so we don't compare those bits * either. */ static long rxrpc_local_cmp_key(const struct rxrpc_local *local, const struct sockaddr_rxrpc *srx) { long diff; diff = ((local->srx.transport_type - srx->transport_type) ?: (local->srx.transport_len - srx->transport_len) ?: (local->srx.transport.family - srx->transport.family)); if (diff != 0) return diff; switch (srx->transport.family) { case AF_INET: /* If the choice of UDP port is left up to the transport, then * the endpoint record doesn't match. */ return ((u16 __force)local->srx.transport.sin.sin_port - (u16 __force)srx->transport.sin.sin_port) ?: memcmp(&local->srx.transport.sin.sin_addr, &srx->transport.sin.sin_addr, sizeof(struct in_addr)); #ifdef CONFIG_AF_RXRPC_IPV6 case AF_INET6: /* If the choice of UDP6 port is left up to the transport, then * the endpoint record doesn't match. */ return ((u16 __force)local->srx.transport.sin6.sin6_port - (u16 __force)srx->transport.sin6.sin6_port) ?: memcmp(&local->srx.transport.sin6.sin6_addr, &srx->transport.sin6.sin6_addr, sizeof(struct in6_addr)); #endif default: BUG(); } } /* * Allocate a new local endpoint. */ static struct rxrpc_local *rxrpc_alloc_local(struct rxrpc_net *rxnet, const struct sockaddr_rxrpc *srx) { struct rxrpc_local *local; local = kzalloc(sizeof(struct rxrpc_local), GFP_KERNEL); if (local) { refcount_set(&local->ref, 1); atomic_set(&local->active_users, 1); local->rxnet = rxnet; INIT_HLIST_NODE(&local->link); INIT_WORK(&local->processor, rxrpc_local_processor); init_rwsem(&local->defrag_sem); skb_queue_head_init(&local->reject_queue); skb_queue_head_init(&local->event_queue); local->client_bundles = RB_ROOT; spin_lock_init(&local->client_bundles_lock); spin_lock_init(&local->lock); rwlock_init(&local->services_lock); local->debug_id = atomic_inc_return(&rxrpc_debug_id); memcpy(&local->srx, srx, sizeof(*srx)); local->srx.srx_service = 0; trace_rxrpc_local(local->debug_id, rxrpc_local_new, 1, NULL); } _leave(" = %p", local); return local; } /* * create the local socket * - must be called with rxrpc_local_mutex locked */ static int rxrpc_open_socket(struct rxrpc_local *local, struct net *net) { struct udp_tunnel_sock_cfg tuncfg = {NULL}; struct sockaddr_rxrpc *srx = &local->srx; struct udp_port_cfg udp_conf = {0}; struct sock *usk; int ret; _enter("%p{%d,%d}", local, srx->transport_type, srx->transport.family); udp_conf.family = srx->transport.family; udp_conf.use_udp_checksums = true; if (udp_conf.family == AF_INET) { udp_conf.local_ip = srx->transport.sin.sin_addr; udp_conf.local_udp_port = srx->transport.sin.sin_port; #if IS_ENABLED(CONFIG_AF_RXRPC_IPV6) } else { udp_conf.local_ip6 = srx->transport.sin6.sin6_addr; udp_conf.local_udp_port = srx->transport.sin6.sin6_port; udp_conf.use_udp6_tx_checksums = true; udp_conf.use_udp6_rx_checksums = true; #endif } ret = udp_sock_create(net, &udp_conf, &local->socket); if (ret < 0) { _leave(" = %d [socket]", ret); return ret; } tuncfg.encap_type = UDP_ENCAP_RXRPC; tuncfg.encap_rcv = rxrpc_input_packet; tuncfg.sk_user_data = local; setup_udp_tunnel_sock(net, local->socket, &tuncfg); /* set the socket up */ usk = local->socket->sk; usk->sk_error_report = rxrpc_error_report; switch (srx->transport.family) { case AF_INET6: /* we want to receive ICMPv6 errors */ ip6_sock_set_recverr(usk); /* Fall through and set IPv4 options too otherwise we don't get * errors from IPv4 packets sent through the IPv6 socket. */ fallthrough; case AF_INET: /* we want to receive ICMP errors */ ip_sock_set_recverr(usk); /* we want to set the don't fragment bit */ ip_sock_set_mtu_discover(usk, IP_PMTUDISC_DO); /* We want receive timestamps. */ sock_enable_timestamps(usk); break; default: BUG(); } _leave(" = 0"); return 0; } /* * Look up or create a new local endpoint using the specified local address. */ struct rxrpc_local *rxrpc_lookup_local(struct net *net, const struct sockaddr_rxrpc *srx) { struct rxrpc_local *local; struct rxrpc_net *rxnet = rxrpc_net(net); struct hlist_node *cursor; const char *age; long diff; int ret; _enter("{%d,%d,%pISp}", srx->transport_type, srx->transport.family, &srx->transport); mutex_lock(&rxnet->local_mutex); hlist_for_each(cursor, &rxnet->local_endpoints) { local = hlist_entry(cursor, struct rxrpc_local, link); diff = rxrpc_local_cmp_key(local, srx); if (diff != 0) continue; /* Services aren't allowed to share transport sockets, so * reject that here. It is possible that the object is dying - * but it may also still have the local transport address that * we want bound. */ if (srx->srx_service) { local = NULL; goto addr_in_use; } /* Found a match. We want to replace a dying object. * Attempting to bind the transport socket may still fail if * we're attempting to use a local address that the dying * object is still using. */ if (!rxrpc_use_local(local)) break; age = "old"; goto found; } local = rxrpc_alloc_local(rxnet, srx); if (!local) goto nomem; ret = rxrpc_open_socket(local, net); if (ret < 0) goto sock_error; if (cursor) { hlist_replace_rcu(cursor, &local->link); cursor->pprev = NULL; } else { hlist_add_head_rcu(&local->link, &rxnet->local_endpoints); } age = "new"; found: mutex_unlock(&rxnet->local_mutex); _net("LOCAL %s %d {%pISp}", age, local->debug_id, &local->srx.transport); _leave(" = %p", local); return local; nomem: ret = -ENOMEM; sock_error: mutex_unlock(&rxnet->local_mutex); if (local) call_rcu(&local->rcu, rxrpc_local_rcu); _leave(" = %d", ret); return ERR_PTR(ret); addr_in_use: mutex_unlock(&rxnet->local_mutex); _leave(" = -EADDRINUSE"); return ERR_PTR(-EADDRINUSE); } /* * Get a ref on a local endpoint. */ struct rxrpc_local *rxrpc_get_local(struct rxrpc_local *local) { const void *here = __builtin_return_address(0); int r; __refcount_inc(&local->ref, &r); trace_rxrpc_local(local->debug_id, rxrpc_local_got, r + 1, here); return local; } /* * Get a ref on a local endpoint unless its usage has already reached 0. */ struct rxrpc_local *rxrpc_get_local_maybe(struct rxrpc_local *local) { const void *here = __builtin_return_address(0); int r; if (local) { if (__refcount_inc_not_zero(&local->ref, &r)) trace_rxrpc_local(local->debug_id, rxrpc_local_got, r + 1, here); else local = NULL; } return local; } /* * Queue a local endpoint and pass the caller's reference to the work item. */ void rxrpc_queue_local(struct rxrpc_local *local) { const void *here = __builtin_return_address(0); unsigned int debug_id = local->debug_id; int r = refcount_read(&local->ref); if (rxrpc_queue_work(&local->processor)) trace_rxrpc_local(debug_id, rxrpc_local_queued, r + 1, here); else rxrpc_put_local(local); } /* * Drop a ref on a local endpoint. */ void rxrpc_put_local(struct rxrpc_local *local) { const void *here = __builtin_return_address(0); unsigned int debug_id; bool dead; int r; if (local) { debug_id = local->debug_id; dead = __refcount_dec_and_test(&local->ref, &r); trace_rxrpc_local(debug_id, rxrpc_local_put, r, here); if (dead) call_rcu(&local->rcu, rxrpc_local_rcu); } } /* * Start using a local endpoint. */ struct rxrpc_local *rxrpc_use_local(struct rxrpc_local *local) { local = rxrpc_get_local_maybe(local); if (!local) return NULL; if (!__rxrpc_use_local(local)) { rxrpc_put_local(local); return NULL; } return local; } /* * Cease using a local endpoint. Once the number of active users reaches 0, we * start the closure of the transport in the work processor. */ void rxrpc_unuse_local(struct rxrpc_local *local) { if (local) { if (__rxrpc_unuse_local(local)) { rxrpc_get_local(local); rxrpc_queue_local(local); } } } /* * Destroy a local endpoint's socket and then hand the record to RCU to dispose * of. * * Closing the socket cannot be done from bottom half context or RCU callback * context because it might sleep. */ static void rxrpc_local_destroyer(struct rxrpc_local *local) { struct socket *socket = local->socket; struct rxrpc_net *rxnet = local->rxnet; _enter("%d", local->debug_id); local->dead = true; mutex_lock(&rxnet->local_mutex); hlist_del_init_rcu(&local->link); mutex_unlock(&rxnet->local_mutex); rxrpc_clean_up_local_conns(local); rxrpc_service_connection_reaper(&rxnet->service_conn_reaper); ASSERT(!local->service); if (socket) { local->socket = NULL; kernel_sock_shutdown(socket, SHUT_RDWR); socket->sk->sk_user_data = NULL; sock_release(socket); } /* At this point, there should be no more packets coming in to the * local endpoint. */ rxrpc_purge_queue(&local->reject_queue); rxrpc_purge_queue(&local->event_queue); } /* * Process events on an endpoint. The work item carries a ref which * we must release. */ static void rxrpc_local_processor(struct work_struct *work) { struct rxrpc_local *local = container_of(work, struct rxrpc_local, processor); bool again; trace_rxrpc_local(local->debug_id, rxrpc_local_processing, refcount_read(&local->ref), NULL); do { again = false; if (!__rxrpc_use_local(local)) { rxrpc_local_destroyer(local); break; } if (!skb_queue_empty(&local->reject_queue)) { rxrpc_reject_packets(local); again = true; } if (!skb_queue_empty(&local->event_queue)) { rxrpc_process_local_events(local); again = true; } __rxrpc_unuse_local(local); } while (again); rxrpc_put_local(local); } /* * Destroy a local endpoint after the RCU grace period expires. */ static void rxrpc_local_rcu(struct rcu_head *rcu) { struct rxrpc_local *local = container_of(rcu, struct rxrpc_local, rcu); _enter("%d", local->debug_id); ASSERT(!work_pending(&local->processor)); _net("DESTROY LOCAL %d", local->debug_id); kfree(local); _leave(""); } /* * Verify the local endpoint list is empty by this point. */ void rxrpc_destroy_all_locals(struct rxrpc_net *rxnet) { struct rxrpc_local *local; _enter(""); flush_workqueue(rxrpc_workqueue); if (!hlist_empty(&rxnet->local_endpoints)) { mutex_lock(&rxnet->local_mutex); hlist_for_each_entry(local, &rxnet->local_endpoints, link) { pr_err("AF_RXRPC: Leaked local %p {%d}\n", local, refcount_read(&local->ref)); } mutex_unlock(&rxnet->local_mutex); BUG(); } }